Alternative Names

How the Test is Performed

You may be asked to wear a hospital gown or clothing without zippers or snaps (such as sweatpants and a t-shirt). Certain types of metal can cause blurry images.

You will lie on a narrow table, which slides into a large tunnel-shaped scanner.

Some exams require a special dye (contrast). Most of the time, the dye will be given through a vein (IV) in your hand or forearm before the test. The dye helps the radiologist see certain areas more clearly.

Small devices, called coils, may be placed around the head, arm, or leg, or around other areas to be studied. These help send and receive the radio waves, and improve the quality of the images.

During the MRI, the person who operates the machine will watch you from another room. The test lasts about 30 to 60 minutes, but may take longer.

How to Prepare for the Test

You may be asked not to eat or drink anything for 4 to 6 hours before the scan.

Tell your health care provider if you are afraid of close spaces (have claustrophobia). You may be given a medicine to help you feel sleepy and less anxious, or your provider may suggest an open MRI, in which the machine is not as close to the body.

Normal Results

A normal result means the body area being studied looks normal.

What Abnormal Results Mean

Results depend on the part of the body being examined and the nature of the problem. Different types of tissues send back different MRI signals. For example, healthy tissue sends back a slightly different signal than cancerous tissue. Consult your provider with any questions and concerns.

Risks

MRI does not use ionizing radiation. No side effects from the magnetic fields and radio waves have been reported.

The most common type of contrast (dye) used is gadolinium. It is very safe. Allergic reactions can occur but are rare. Gadolinium may be harmful to people with kidney problems who are on dialysis. Tell your provider before the test if you have kidney problems.

The strong magnetic fields created during an MRI can cause heart pacemakers and other implants not to work as well. The magnets can also cause a piece of metal inside your body to move or shift.